FIG. 1 is an illustrtion of a microsurgical knife 10 including a knife body 12 having a cutting blade 14 at one end thereof. More specifically, the knife body 12 includes a forward portion 13 that tapers downwardly towards blade 14 to provide good visibility of the cutting tip. The knife body 12 has a gripping surface 12a that may be knurled or otherwise roughened to provide a secure grip. Microsurgical knife 10 in disposable form is manufactured by the assignee of the present application. The microsurgical knives 10 are shipped in vacuum formed trays of the type disclosed in U.S patent application Ser. No. 739,217 filed May 30, 1985, assigned to the present assignee. Said vacuum formed tray is essentially of a type providing snapfitting securement between the knife body and portions of the tray. The knife is easily removed from the tray although securely and snugly held while in the tray and prior to introduction to the sterile field.
It has recently been discovered that knives 10 are occasionally being introduced to the sterile field with the knife blades 14 in a bent and therefore unsatisfactory condition. It is believed that the damage may occur when the knife 10 is removed from the vacuum formed tray for introduction to the sterile field. It is further suspected that such damage to the blade 14 occurs as the rear end of knife body 12 remote from blade 14 is manually lifted from the surface of the tray causing possible and undesirable bending contact between the knife blade and tray body.
In light of the above problem, it would be desirable to provide a structure for protecting the structural integrity of the cutting blade 14 until knife 10 is introduced to the sterile field. Such a structure should be simple to manufacture and therefore economical while requiring economy of effort in attachment and subsequent detachment from the knife body.
U.S. Pat. No. 4,576,164 to Richeson discloses a disposable microsurgical knife having a shroud that can be locked into a position protecting a blade located at one end of the knife body. The cylindrical shroud is in the form of a sheath that is movable axially along the knife body. The shroud is formed with a plurality of projections mating with a complex arrangement of longitudinal and circumferential grooves formed on the exterior surface of the knife body. This complicated arrangement of grooves on the knife body allows the shroud to be locked in two or three positions wherein in one position the shroud in fact acts as an enlarged centrally located handle which may discourage use of the knife by various surgeons. If the shroud were to be removed entirely from the knife body, the exposed system of complicated longitudinal and circumferential grooves may result in an inconvenient grip for the surgeon. Thus, the locking shroud disclosed in the aforesaid patent has many distinct disadvantages.
U.S. Pat. Nos. 3,706,106; 3,905,101; 3,945,117; and 4,414,974 disclose other types of surgical knives having movable blade protective structures.
It is accordingly one object of the present invention to provide a surgical knife having a removable guard for protecting the blade during shipping or otherwise prior to introduction to the sterile field.
It is another object of the present invention to provide a disposable microsurgical knife with a blade guard that is easily attached to entirely cover the cutting blade of the knife so that the blade will not be damaged in shipping and will remain in protective position until easy removable prior to introduction to the sterile field.
Still a further object is to provide a guard capable of easy yet positive locking engagement with the microsurgical knife body and which utilizes locking structure that does not interfere with the grip provided for the surgeon on the knife body when the guard is removed from the knife.